English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Co-occurrence of denitrification and nitrogen fixation in a meromictic lake, Lake Cadagno (Switzerland)

MPS-Authors
/persons/resource/persons210431

Halm,  H.
Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210622

Musat,  N.
Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210560

Lam,  P.
Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210621

Musat,  F.
Department of Microbiology, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210568

Lavik,  G.
Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210765

Schubert,  C.J.
Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Max Planck Society;

/persons/resource/persons210556

Kuypers,  M.M.M.
Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Max Planck Society;

External Ressource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Halm, H., Musat, N., Lam, P., Langlois, R., Musat, F., Peduzzi, S., et al. (2009). Co-occurrence of denitrification and nitrogen fixation in a meromictic lake, Lake Cadagno (Switzerland). Environmental Microbiology, 11(8), 1945-1958.


Cite as: http://hdl.handle.net/21.11116/0000-0001-CBDE-1
Abstract
The nitrogen cycling of Lake Cadagno was investigated by using a combination of biogeochemical and molecular ecological techniques. In the upper oxic freshwater zone inorganic nitrogen concentrations were low (up to approximately 3.4 microM nitrate at the base of the oxic zone), while in the lower anoxic zone there were high concentrations of ammonium (up to 40 microM). Between these zones, a narrow zone was characterized by no measurable inorganic nitrogen, but high microbial biomass (up to 4 x 10(7) cells ml(-1)). Incubation experiments with (15)N-nitrite revealed nitrogen loss occurring in the chemocline through denitrification (approximately 3 nM N h(-1)). At the same depth, incubations experiments with (15)N(2)- and (13)C(DIC)-labelled bicarbonate, indicated substantial N(2) fixation (31.7-42.1 pM h(-1)) and inorganic carbon assimilation (40-85 nM h(-1)). Catalysed reporter deposition fluorescence in situ hybridization (CARD-FISH) and sequencing of 16S rRNA genes showed that the microbial community at the chemocline was dominated by the phototrophic green sulfur bacterium Chlorobium clathratiforme. Phylogenetic analyses of the nifH genes expressed as mRNA revealed a high diversity of N(2) fixers, with the highest expression levels right at the chemocline. The majority of N(2) fixers were related to Chlorobium tepidum/C. phaeobacteroides. By using Halogen In Situ Hybridization-Secondary Ion Mass Spectroscopy (HISH-SIMS), we could for the first time directly link Chlorobium to N(2) fixation in the environment. Moreover, our results show that N(2) fixation could partly compensate for the N loss and that both processes occur at the same locale at the same time as suggested for the ancient Ocean.